(57) This invention provides a frame relay apparatus and a relay method with an efficient transfer time, regardless of the transmitting rates of the input signal and the output signal. A route control table which corresponds the transmitting line number to the transmitting logical link number by using the receiving line number and the received logical link number of the header of the received frame is provided as is a line attribute table which stores the transmitting rates of the input signal and output signal. Furthermore, the line attribute table to store the transmitting rates of the input signal and the output signal and a comparison control mechanism to calculate the necessary buffering amount of the sending buffer based on the frame length of the concerning received frame which is gotten at or before the receiving time of the data of the received frame are provided. Additionally, a transmitting handler mechanism is provided to start a transmission immediately when the transmission rate of the designated transmitting line is equal to or lower than the transmitting rate of the input signal, and to start a transmission after storing the transmission data up to the required buffering amount when the transmitting rate of the input signal is higher than the transmitting rate of the output signal.